/Engine/Source/Runtime/PakFile/Public/IPlatformFilePak.h
Returns the RelativePathFromMount Filename for every Filename found in the Pruned DirectoryIndex that points to a PakEntry in the given Chunk
void GetPrunedFilenamesInChunk ( const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & InChunkIDs, [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & OutFileList ) const